Structure and Formation Mechanisms of AlGaAs V-Groove Vertical Quantum Wells Grown by Low Pressure Organometallic Chemical Vapor Deposition

The structure of AlGaAs vertical quantum well (VQW) structures grown by low-pressure organometallic chemical vapor deposition on V-grooved GaAs substrates was analyzed as a function of growth temperature and Al mole fraction using transmission electron microscopy and atomic force microscopy (AFM). The low-pressure growth yields several, extremely narrow (a few nm wide) branches of Ga-enriched VQWs at the bottom of the grooves, The variation in Al content across the VQW was evaluated by measuring the AlCaAs oxide thickness on a cleaved edge of the structure using AFM in air. The transmission electron microscopy analysis demonstrates that the different VQW branches originate from distinct nanofacets that self-order at the bottom of the V-groove, probably due to facet-induced segregation of group III species.